Concrete structures are made off site in a purpose built yard then transported to site and lifted into position.
An example of precast that we have done is work for St Marys, Isles of Scilly. The precast units will later be used to form the jetty on the island. Key widening blocks will be used as for an extension to the quay.
We also did work at the Exeter Transfer Station. The walls were precast off site, taken to site and then dropped into position. The precast walls were 5m tall.